1. Field of the Invention
The present invention relates to a method and apparatus for detecting motion vectors of an image.
2. Description of the Related Art
If a video is displayed on an image display device using a liquid crystal panel, a motion blur is likely to be generated. Thus, in order to improve a video characteristic by reducing a motion blur, the number of frames is increased by interpolating compensated frames between real frames of an image signal, for example, an image is displayed by converting a frame rate (frame frequency) having a vertical frequency of 60 Hz to double, i.e., 120 Hz, or more. An image display device displaying images by converting a frame rate of a signal detects a motion vector of an image, generates each interpolation pixel by using the motion vector, and then, generates an interpolation frame that is interpolated between actual frames.
The motion vector is detected by estimation based on pixels within a defined number of frames among successive frames, and it is difficult to detect the motion vector without a false detection. For example, when a front view image on a front portion spatially and a background view image on a rear portion spatially move different from each other, a false detection of the motion vector is likely to occur. A method of improving an accuracy of detecting motion vectors in the above case is disclosed in Patent Document 1. A motion vector detecting apparatus disclosed in the Patent Document 1 detects motion vectors based on each of front and rear frames, and designates a motion vector having higher correlation as a final motion vector. Accordingly, a false detection of a motion vector may be reduced.
In a configuration of detecting the motion vectors based on each of front and rear frames disclosed in the Patent Document 1, two circuits for detecting the motion vectors are necessary, and thus, a circuit scale increases to thus increase costs. Thus, it is necessary to restrain an increase of the circuit scale.    (Patent Reference 1) Japanese Laid-open Patent Publication No. 2011-82846